Sewing thread



United States Patent Office 3,368,343 Patented Feb. 13, 1968 3,368,343 SEWING THREAD Alan Crook, Manchester, and Michael John Horrobin, Choriey, England, assignors to English Sewing Cotton Company Limited, Manchester, England, a British company No Drawing. Filed Mar. 24, 1965, Ser. No. 458,408 Claims priority, application Great Britain, May 28, 1964, 22,049/ 64 14 Claims. (Cl. 57-140) ABSTRACT OF THE DISCLOSURE Sewing thread made of not less than two nor more than six substantially transparent and colorless or substantially translucent filaments of synthetic material twisted together. The thread takes on the color of the fabric into which it is stitched and facilitates sewing since the thread is not unduly stiff.

The present invention relates to sewing thread made of man-made filaments of synthetic material, for example nylon.

Man-made filaments are made by extruding liquid material through a spinneret provided with holes, and solidifying the liquid material. The solid product from one hole of the spinneret is a filament. A thread comprises a number of such filaments twisted together.

Generally sewing threads made from synthetic materials consist of a substantial number of filaments twisted together, for example as many as two hundred filaments. A very fine thread may consist of two yarns twisted together and having a total of twenty-four filaments. The filaments in multi-filarnent sewing threads are usually finer than 6 denier. Thus a 120 denier thread may consist of two yarns each having twenty filaments of 3 denier each, or forty filaments of 1 /2 denier each, whilst a coarser thread of 630 total denier may-consist of three yarns each having one hundred and forty filaments of 1 /2 denier each. The surfaces of the filaments within such threads scatter the light to such an extent that little if any light is transmitted through the thread. Such a thread in a seam appears white, if the filaments therein are colourless.

Such sewing threads must therefore be stocked by garment makers dyed to a large number of colours and shades of colours to match fabrics to be seamed. There is a considerable wastage of thread and operatives time when threads are changed frequently for seaming garments of difierent colours, and also as a result of changes in fashion.

It has been proposed to useas sewing thread a single filament of 80 denier and coarser of colourless synthetic material, for example nylon. Such thread is, however, stiff and the seam formed is rough and harsh. Difficulties can occur in sewing because of the stiffness of the thread. Such sewing thread is therefore unsuitable for many sorts of seams. Furthermore, because the thread is stilf it does not lie close to some types of fabric or other material seamed with it, and so it remains visible.

According to the present invention sewing thread comprises not less than two and not more than six substantially transparent or translucent and colourless or nearly colourless filaments of synthetic material twisted together.

A further feature of the invention resides in sewing thread comprising not less than two and not more than four such filaments twisted together.

A still further feature of the invention resides in sewing thread comprising not less than three and not more than six such filaments twisted together.

Further features of the invention reside in sewing thread comprising either three or four such filaments twisted together.

Preferably the sewing thread of the present invention has a breaking strength of at least 250 gms. when tested in accordance with British standard specification No. 1932. The filaments are preferably twisted together at from four to eight turns per inch and the twisted filaments may be heat set.

In seams sewn wtih sewing thread of the invention, the thread tends to take on the colour of the fabric into which it is stitched and this property of the thread is substantially independent of the denier of the filaments. At the same time threads made according to this invention and the seams formed with them are not unduly stiff. This not only facilitates sewing, but it also has the advantage that the thread in the stitched seam lies closer to the fabric. Seams therefore sewn with thread made according to this invention tend to be generally less visible than seams sewn with the known multi-filament threads hereinbefore discussed or even with single filament threads. The threads also can absorb more lubricating material when treated with lubricants than single filament threads.

Whilst the filaments used for the thread of this invention are generally transparent or colourless, and the seams sewn with the threads are less visible than normal threads on fabric of all colours, the effect with dark coloured fabrics, for example black or dark blue, may be improved if the filaments are pigmented lightly with a dark pigment, for example black or dark blue.

The present invention further consists of a method of manufacturing sewing thread by twisting together two or more, but not more than six, filaments of colourless or nearly colourless and substantially transparent or translucent synthetic material. The twisting may be carried out at the same time as the filaments are extruded but as a rule without adhesion between the filaments.

We have found that the amount of twist given to the yarn or thread has little influence on its capacity to take on the colour of the farbic stitched with it when it is used as sewing thread. Generally we have found that it is convenient to use about six turns per inch.

Preferably the thread is heat set after twisting, for example by steaming, to eliminate snarling and untwisting particularly when the thread is cut. Alternatively, or in addition, the filaments may be lightly bonded together with a bonding agent.

Suitable synthetic materials for the manufacture of sewing thread according to the invention include polyester filaments such as those sold under the registered trade mark Terylene, and also polypropylene, but we prefer to use nylon, for example of the type sold as nylon 6 and 66, because of its combination of properties-high melting point and strength with good flexibility-all of which are very desirable in sewing thread.

The larger the number of filaments in the threads made according to the present invention the less exactly does the thread in the seam stitched with it take on the colour of the fabric which is being stitched. We prefer therefore to use threads composed of not more than four filaments.

The denier of the threads and filaments and the number of filaments of the threads of the present invention should be chosen according to the use which is to be made of them. For example, satisfactory nylon sewing threads made according to the present invention for particular purposes are as follows:

(a) For general seaming operations, for example lock stitch or overlook seams, on dress fabric: a thread composed of three filaments or colourless nylon 6, each filament being of 30 denier. Alteratively, filaments of nylon 66 or nylon 11 may be used. Alternatively, two filaments of 50 denier each may be used.

(b) For sewing materials such as leather, a thread composed of four filaments of colourless nylon 66, each filament being of 60 denier, the thread having been lubricated by treatment with 5% by weight of silicone oil. Again nylon 6 or nylon 11 may alternatively be used. For heavier work six filaments of 80 denier each may be used.

(c) For general seaming operations on navy blue or black suitings fabrics or felts: a thread composed of four laments of nylon 6 of 40 denier lightly pigmented with black pigment to smoke shade.

With these threads satisfactory seams can be sewn which are not rough or harsh, and the seams appear to be of substantially the same colour as the coloured materials sewn, although the threads themselves are colourless or substantially so.

We claim:

1. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than three and not more than four substantially transparent and colorless filaments of synthetic material twisted together, said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

2. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than three and not more than six substantially transparent and colorless filaments of synthetic material twisted together, said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

3. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than two and not more than four substantially transparent and colorless filaments of synthetic material twisted together, said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

4. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than two and not more than six substantially transparent and colorless filaments of synthetic material twisted together, said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

5. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than two and not more than six nylon filaments twisted together at from four to eight turns per inch, said twisted together filaments being in a set condition, said filaments being transparent and colorless, and said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

6. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than two and not more than four nylon filaments twisted together at from four to eight turns per inch, said filaments being in a set condition, said filaments being transparent and colorless, and said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

7. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than three and not more than six filaments twisted together at from four to eight turns per inch, said filaments being in a set condition, said filaments being transparent and colorless, and said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

8. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than three and not more than four nylon filaments twisted together at from four to eight turns per inch, said filaments being in a set condition, said filaments being transparent and colorless and said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

9. Sewing thread adapted to take on the color of a fabric to which said thread is stitched comprising not less than two and not more than six substantially translucent filaments of synthetic material twisted together, said filaments being of such a thickness that when twisted together they make a thread suitable for sewing.

10. The sewing thread of claim 9 wherein the filaments are made of nylon.

11. A method of making a sewing thread which when stitched to a fabric takes on the color of said fabric comprising:

forming substantially transparent and colorless filaments of synthetic material,

selecting not less than two but not more than six of said filaments,

twisting said filaments together to form a thread suitable for sewing,

and heat setting said filaments after twisting to prevent snarling and untwisting of said sewing thread.

12. Sewing thread according to claim 4 comprising filaments of nylon.

13. Sewing thread according to claim 9 comprising filaments which are pigmented lightly with black pigment.

14. Sewing thread according to claim 9 comprising filaments twisted together at from four to eight turns per inch.

References Cited UNITED STATES PATENTS 2,130,948 9/1938 Carothers 57-14-0 X 2,188,332 1/1940 Carothers 28-1 2,226,529 12/1940 Austin 28-1 2,251,962 8/1941 Sommaripa 57-140 2,265,119 12/1941 Coolidge 28-1 2,483,455 10/1949 Camp 57-157 2,911,784 11/1959 Vandervoort 57-140 3,041,816 7/1962 Stuewer 57-140 3,137,864 6/1964 Ostmann 28-77 3,153,895 10/1964 Eckhardt 57-140 JOHN PETRAKES, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,368,343 February 13, 1968 Alan Crook et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, line 7, for "Filed Mar 24 1965" read Filed May 24 1965 Signed and sealed this 6th day of May 1969.

(SEAL) Edward M. Fletcher, Jr.

Commissioner of Pate ts Attesting Officer 

